There are many cases where a single user may need to access multiple isolated computing systems. Due to security reasons it may be critical that isolated computing systems will not be connected together to prevent potential data leakages and to block certain security attacks. Any peripheral device shared between two or more isolated networks may be a target for external or internal attackers. Common attack strategy is to cause a permanent or temporary data leakage path between the two coupled networks to enable data theft, unauthorized data modification or unauthorized data import. To allow a single user to operate multiple computers coupled to multiple isolated networks KVM (Keyboard Video Mouse) switch may be used. KVM switch connected to one set of user keyboard, mouse and display on one side and to multiple computers on the other side provides the user with the ability to interact with one specific computer at a time.
One specific scenario area of concern is leakage between a classified computer system or network and a non-classified network such as a network attached to the internet. Such leakage may serve as an agent inside the classified network to send classified data to unknown hostile organizations in any location in the world.
Over the past years there were several common solutions for single user operating multiple isolated computers:    1. Using multiple displays and multiple sets of user peripheral devices.            Some organizations are enforcing isolation by placing two or more isolated sets of user peripheral devices on the user's desktop. Isolation is assured as there is no electrical contact between the multiple computers. Major disadvantage of this solution is its inherent reduced usability. Users find it hard to divert their attention between multiple systems. This solution also takes additional valuable user desktop space. If more than two isolated computers needed for a user, these usability and desktop space disadvantages tend to get worsen.            2. Using KVM switch or Secure KVM to enable user interaction with multiple isolated computers through one set of peripherals. This solution reduces the desktop space needed and provides better usability. As conventional KVMs may leak data between coupled isolated computers, in many cases a Secure KVM is used. This type of KVM provides higher assurance that coupled computers would not leak data to one another. While this solution provides better usability, it is not suitable for users that need to see multiple displays simultaneously. Users such as traders need to see various data from multiple sources presented at all time on multiple displays. Although some secure KVMs supporting multiple displays available today, this solution tends to be less flexible and relatively expensive.    3. Using KM (Keyboard Mouse) switch to enable user interaction with multiple isolated computers through multiple isolated displays and one set of keyboard and mouse. Shared keyboard and mouse through software or hardware KM provides access to multiple computers by means of manual switching or even continues virtual display. Unlike KVM the KM switches only the keyboard and mouse, while the display outputs are not passed or switched through the KM.What is needed is a secure KM switch that enables secure isolation between the coupled computers. Such needed device will enable seamless user interaction with the isolated computers while viewing multiple displays. The needed secure KM switch will require minimal software and hardware installation in the coupled computers.
Information on some commercially available systems may be found in:                1. Adder TS4 Four-port keyboard and mouse switch User's Manual (http://www.adder.com/uk/products/Manuals/TS4/ADDER_TS4_v1_1c.pdf)        2. Adder CCS4USB Four-port keyboard and mouse switch User's Manual (http://www.adder.com/UK/products/Manuals/CCS4-USB/AdderCCS4-USBv2-0d.pdf)        3. Actionstar USB KM switch specifications (http://www.actionstar.com.tw/products_details.php?l=0&pro_id=81)        4. Waterfall Remote Screen View, from Waterfall™ Security Solutions Ltd. (http://www.waterfallsecurity.com/remote-screen-view/)        5. Multiplicity from Stardock Corporation, (http://www.stardock.com/products/multiplicity/)        